In the past, check valves for air lines have included a two-piece housing (as shown in FIG. 1) with the two pieces permanently joined together. Such prior art check valves also included a resilient disc captured between the inseparable halves to provide the one-way flow characteristic.
Such prior art check valves were not serviceable and required replacement of the entire check valve in the event of contamination or wear out of any of the parts of the valve.